Secondary objectives: To describe the epidemiological characteristics of community-acquired bacterial meningitis in adults, changes in these characteristics and their relations with the vaccine status of the affected adult and his/her family; to characterize clinical and microbiological failures and their determinants (pharmacological, microbiological, immunological, etc.); to analyse the determinants of neurosensory sequelae and failure to return to work after 1 month, 6 months and 12 months.